reharmonization

Reharmonization is the practice of changing the harmonic backdrop of a melody by substituting different chords while preserving the melody itself. It is used in jazz, pop, film music, and sometimes classical contexts to alter color, emotional impact, or structural feel without rewriting the tune. Reharmonization can occur on a small scale within a phrase or across larger sections, and it often interacts with rhythm and tempo to broaden musical expression.

Common techniques include the use of secondary dominants and tonicizations, where dominant chords are inserted to emphasize upcoming chords (for example, V7/ii leading to ii). Modal mixture or borrowed chords from parallel keys expands harmonic color, such as borrowing from minor or parallel modes. Chromatic mediants and planing involve moving chords in parallel motion by third intervals or in smooth chromatic steps to create unexpected color. Tritone substitutions replace a dominant chord with another dominant a tritone away, altering voice-leading while preserving function. Other approaches include diatonic substitutions within a functional framework, diminished passing chords, chromatic approach chords, and the use of pedal points that keep a common tone while chords move underneath.

Applications vary by genre but share a goal of giving a familiar melody new life or emotional shading. In jazz, reharmonization is a standard improvisational and arranging tool; in pop and film music it can provide mood shifts or climactic moments. In practice, composers analyze a tune’s harmony and experiment with substitutions, balancing novelty with melodic clarity.